1. Field of the Invention
The present invention relates generally to flow control valves and, more particularly, to an apparatus for regulating either the upstream or downstream pressure of fluid being controlled by the apparatus.
2. Description of the Prior Art
It is known to provide valve devices in fluid supply systems for controlling the fluid pressure at a desired location in the system. For example, in a fluid dispensing arrangement, it is conventional to provide a pressure regulating valve apparatus upstream of a dispensing device in order to control the pressure of fluid being pumped to the dispensing device.
In this known type of system, the regulating device is referred to as a downstream pressure regulator because it controls the pressure of fluid downstream of the valve apparatus and maintains a desired predetermined pressure of fluid at the dispensing apparatus. It is also possible to have similar applications where an upstream regulating valve apparatus is used which maintains a predetermined pressure in the fluid upstream of the valve.
Although these known pressure regulating devices have been found satisfactory in numerous applications, certain drawbacks are evident when such devices are employed in systems requiring a regulation of the pressure of clean fluids such as ingestible medicines or beverages. In the food industry, it is necessary to provide a relatively smooth surface throughout the flow path of fluids being dispensed in order to reduce the opportunity for the fluid to get caught up within the system and stagnate. Thus, it is important to present as few voids and interstices as possible to the fluid in an effort to reduce such stagnation. Further, frequent cleaning of all fluid dispensing equipment is necessary in order to protect against the presence of germs in the system which adversely effect the quality of the fluids being handled.
In view of these special needs in the food and medicine industries, it may be understood that a regulating device having a complex internal mechanical construction would not be well suited for use in regulating the pressure of an ingestible fluid. Such intricate constructions result in a device which is difficult to clean and which permits fluid to get caught up in voids and interstices within the fluid flow path such that stagnation is promoted.